Laser Sail, Maser Sail
Solar sail
Image from Steve Bowers

Laser Sails

Laser sails use thin multi-square-kilometer sails (often several hundreds of kilometres in diameter) made of ultra-light reflective material. These are propelled by visible-light lasers with up to thousands of terawatts of power, allowing a reasonable rate of acceleration with no on-board reaction mass. Generally used for unmanned craft.

Maser Sails

Image from Steve Bowers
The Starwisp, the first successful interstellar probe to any destination, reached Alpha Centauri in 202 AT
Maser sails use microwave laser beams, or masers, for propulsion, and consist of a thin mesh capable of interacting with the longer wavelength of these beams. Many early interstellar probes used maser sails, sometimes including an extra reflective element to allow deceleration. Even in the current era lightweight maser-sail probes are sometimes used for exploration purposes.

Heavier craft often use magnetic drive sails to interact with a smart particle beam, which carries considerably more momentum.

See also Laser Launching systems
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Development Notes
Text by M. Alan Kazlev
Additional material by Steve Bowers
Initially published on 03 December 2001.